Current planar radiating element and manifold technology using high dielectric constant materials cannot provide a single manifold and radiating element feed layer, good polarization performance and compact power divider with good isolation. Conventional probe fed patch apertures have gain and polarization limitations in the H plane scan.
Electronically scanned antennas generally comprise a manifold layer for distributing power to a feed layer. The feed layer feeds power to an aperture layer that converts the power to signals in free space. The aperture layer typically requires low dielectric constant materials that are unsuitable for FR-4 manufacturing processes. Furthermore, existing aperture layers are substantially thicker than the manifold or feed layers, creating an unbalanced circuit board.
Probe fed apertures generally comprise a low dielectric substrate and two printed circuit board patches. Patches tend to scatter into lower order Floquet modes. Lower order Floquet modes must be relatively constant for all scan angles, necessitating a small unit cell size and a low dielectric constant substrate. The small unit cell size means that the module density is high, significantly increasing the cost of the antenna. The properties of the materials mean that the probe fed apertures are vulnerable to temperature cycles. Furthermore, aperture performance as a function of frequency at array normal and 60° in theHplane is sub-optimal. Cross-polar coupling at wide H plane scan angles is also high because the probe must be asymmetrical in the H plane.
Consequently, it would be advantageous if an apparatus existed that is efficient to manufacture and suitable for use as a radiating element having good balance, good polarization performance and compact power divider delivery mechanism.